I notice some posts an Linear and Abstract Algebra have the 'proper' symbols for R, Z, C etc - how is this done?
They are not "proper" symbols for these things, the proper symbols (if that has any meaning) are just bold R, Z, C ... What you are referring to are the "black board bold" symbols which are a type face which mimics how the standard bold characters are written on a black board. But then these seem to be more or less standard, and someone else has already told you how to generate them.
an amusing tale of a font modelled after a blackboard approximation of yet another font, that is slowly replacing the font it was once just a "stand-in" for. oh the back-biting backwaters of math symbolism!